This invention was made in the course of or under a contract or subcontract with the Department of the Army.
This invention relates to a new and improved aerodynamic window for a laser operating at very low cavity pressure.
Many types of gas lasers such as chemical lasers, gas dynamic lasers, transfer lasers, and in general, those lasers which operate at low cavity pressure, require that the optical cavity be enclosed to maintain a suitable pressure differential between the cavity and atmosphere. At relatively low power, the use of an optical window may be employed in a chemical laser because the effect of heat distortion and optical integrity are not too severe.
However, at high power, optical windows become very hot and either break or lose their properties of good optical transmission due to heat distortion.
Consequently, aerodynamic windows have been developed for gas dynamic lasers to eliminate the necessity for passing the output beam through a solid optical window. A summary of such windows is given by Zimet, E., "Aerodynamic Windows for Laser Beams", Naval Ordinance Laboratory Report No. NOLTR-73-66, 1973. These prior art aerodynamic windows degrade the laser beam quality significantly and ingest gas into the laser cavity.
It is therefore an object of this invention to provide a high power laser operating at low cavity pressure with a simple aerodynamic window which passes a laser beam from the cavity to the atmosphere with a minimum of beam distortion and no gas leakage into the laser cavity.
Other objects of the invention will become apparent from the description and drawings to follow.